sume
the points of extreme darkness for a basis, and to light everything
above these in due proportion, till the mass of the picture is lost in
light.

170. Thus, in Turner's sepia drawing "Isis" (Edu. 31), he begins with
the extreme light in the sky, and shades down from that till he is
forced to represent the near trees and pool as one mass of blackness. In
his drawing of the Greta (S. 2), he begins with the dark brown shadow of
the bank on the left, and illuminates up from that, till, in his
distance, trees, hills, sky, and clouds, are all lost in broad light, so
that you can hardly see the distinction between hills and sky. The
second of these methods is in general the best for colour, though great
painters unite both in their practice, according to the character of
their subject. The first method is never pursued in colour but by
inferior painters. It is, nevertheless, of great importance to make
studies of chiaroscuro in this first manner for some time, as a
preparation for colouring; and this for many reasons, which it would
take too long to state now. I shall expect you to have confidence in me
when I assure you of the necessity of this study, and ask you to make
good use of the examples from the Liber Studiorum which I have placed in
your Educational series.

171. III. Whether in formal or aerial chiaroscuro, it is optional with
the student to make the local colour of objects a part of his shadow, or
to consider the high lights of every colour as white. For instance, a
chiaroscurist of Lionardo's school, drawing a leopard, would take no
notice whatever of the spots, but only give the shadows which expressed
the anatomy. And it is indeed necessary to be able to do this, and to
make drawings of the forms of things as if they were sculptured, and had
no colour. But in general, and more especially in the practice which is
to guide you to colour, it is better to regard the local colour as part
of the general dark and light to be imitated; and, as I told you at
first, to consider all nature merely as a mosaic of different colours,
to be imitated one by one in simplicity. But good artists vary their
methods according to their subject and material. In general, Duerer takes
little account of local colour; but in woodcuts of armorial bearings
(one with peacock's feathers I shall get for you some day) takes great
delight in it; while one of the chief merits of Bewick is the ease and
vigour with which he uses his bla